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Discussion Starter #1 (Edited)
Reflecting on @NewsCoulomb and his 100,000 miles in a BOLT, I appreciated his comment that the BOLT EV improves with age because it can take advantage of a growing charging network.

If the vehicle is part of a network, what makes that combination desirable? I argue that the forum members have already spoken. We all want long range, well-located DCFC, and high charge rates.

Placing these ideas in a proportional equation, one can get a number that could represent a VN Merit (Vehicle-Network Merit). (The equation rewards desired factors by placing them in the numerator, where larger is better. Undesirable factors are in the denominator, where smaller the better.)

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It’s a bit of algebra that says:
we want to see a lot of fueling stations between full and empty (the first term) and,
when we get to the fueling station, we want to be able to fill quickly (the second term).

If you translate the second part into battery terms, it's really a definition of C, the charge rate in kW divided by the battery capacity in kWh.

The first question is: What is the typical ICE VN Merit?

We need to first consider the ‘Gasoline’ network. We have about 100,000 fueling locations spread over about 2.96 million square miles of land area in the contiguous US. Distributing these uniformly (I know, gas stations are not uniformly distributed…) we have one gas station every 30 square miles or so. That’s a square of about 5.5 miles on a side (again, I know this should be a hex cell, but it doesn’t change the VN Merit significantly.) On the average, we only need to drive 5.5 miles to get to a gas station.

The ICE vehicle is simple. Just choose any mid-range sedan, hatchback, or CUV. These have a 15-gallon tank and get 30 miles to the gallon. That gives a range of 450 miles.

For fueling, the common gas dispenser has no problem pumping 5 gallons a minute or 180 gallons an hour.

Combining, we get: 450(miles)/5.5(miles) x 180 (gallons/hr.)/15 gallons

ICE VN MERIT 982

How do the EV VN Merits compare?


We all recognize at least three Vehicle-Network ‘environments’

  • A Tesla environment of about 2500 Supercharger locations, cars with ranges of 300 miles, charge rates of 144kW, and batteries of about 70kWh (Tesla M3 LR dual motor).

  • A 50kW environment populated by BOLT and Hyundai Kona that have ranges of around 250 miles, charge rates topping out at 60kW, and about 62kWh batteries. There are about 1,100 evGO or ChargePoint locations, and about 300 EA locations (thanks @Usain) serving this environment.

  • A 100kW plus environment populated by Jaguar iPace, Porsche Taycan, and other super-premium offerings. Batteries are approximately 95kW although EPA driving ranges are in the low 200 miles. To date, only about 300 Electrify America locations serve this network with charge rates of 150kW to 350kW.
Working out the numbers…trust me.
  • Tesla: A supercharger every 35 miles. Tesla VN Merit = 18

  • 50kW world: A charger every 46 miles. 50kW (BOLT) VN Merit = 4.3

  • 350kW world (Porsche Taycan—just for fun: 93kWh battery, 270kW charge rate, 204-mile EPA range): An EA charger every 100 miles.
    Porsche Taycan VN Merit = 5.9
My initial reactions were:

  • If Tesla can achieve sell a lot of TM3s with a VN Merit of 18 compared to an ICE VN Merit of 981, there is a genius in their design.
  • Companies trying to introduce EVs solely on vehicle specifications, without considering a charging network, are going to suffer disappointments. (See: Jaguar iPace, or GM's reluctance to support, collaborate, or invest in charging, etc.)

  • If we are used to an ICE VN Merit of 981, how can many of us be happy with the BOLT? Or a Tesla?
  • If we are happy with the BOLT, or Kona, or Tesla, do we really need all the ICE network?
The last reaction is important. There are about two orders of magnitude of difference between the ICE VN Merit and the EV VN Merit. It’s not 20%. If the EV network works for a lot of drivers, then the ICE network is wildly overbuilt and overcapitalized. That means it can only get squeezed for cash and get smaller. (Do you see private investors running to put up gas stations? )

As @NewsCoulomb implied, EVs will see improvement in their network while ICE will see deterioration of theirs. (There is a long way down—closing 75% of gas stations still gives a VN merit of 500.)

As a last note, there is an interesting little quirk challenging the $150,000+ EV super cars. Rearranging the VN Merit relationship for BEV gives:

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Battery capacity divided by efficiency is just the range in miles. The Battery capacity terms cancel leaving:

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That's surprising.The battery size is not important once you choose the desired range and charging network.


The only metric for VN Merit is the ratio of how fast you can charge divided by how fast you use it.

You can tout 90, 100, 150kWh batteries, but if your design guzzles electrons you need to drive higher and higher charge rates to keep a reasonable VN Metric. Soon, you will run out of chargers or must invest in very new technologies. It's like having a 6mpg 1-ton pickup with 85 gallon saddle tanks; you are going to pay for it in the end.

Just consider the following, calculating only the charge/efficiency ratio.

BOLT (for fun): (50kW charge rate)/(0.256kWh/mile) = 195

Taycan: (270kW charge rate)/(0.455 kWh/mile) = 593
(A Taycan at a 100kW station is not much better than a BOLT; at a 50kW station it looks like a 500e)

TM3: (144kW charge rate)/(0.27kWh/mile)= 533! (Tesla is already near an EA level, and that's before V3 supercharging.)


This is not to mock the Taycan or publicize Tesla. It means the race will go not to the group that builds the biggest, fastest, most ludicrous vehicle, but to the group that builds EVs with a matched network in mind.
 

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I tend to agree that the ICE network is/will be saturated for upcoming demand. As are private repair garages.

Would you factor in home charging as part of the math? Perhaps the EV network gains merit points if we consider that more than half of the nationwide “fuelling” needs are met within 20 feet of where EVs are parked all night?

My wife’s ICE had to be filled 6 times a month... now she pre-heats her Bolt without having to open the garage door for fumes :) .
 

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Would you factor in home charging as part of the math? Perhaps the EV network gains merit points if we consider that more than half of the nationwide “fuelling” needs are met within 20 feet of where EVs are parked all night?

My wife’s ICE had to be filled 6 times a month... now she pre-heats her Bolt without having to open the garage door for fumes :) .
This is the thing about 200+ mile EVs that ICE drivers can't seem to get their heads around. For 90% of most peoples driving, a public charging network is an occasional nuisance at worst, or icing on the cake in the case of Tesla.
 

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Discussion Starter #4
:) I remember panicking the first time I left the BOLT on with the garage closed...

I think you have a good idea. Charge at home means you are never more than 1/2 the daily drive away from a charging station. At 15,000 miles a year that means about 20 miles. The VN Metric would be around 1.5, but that may be OK. Even a Tesla charged on a 9.6kW home charger gets a VN Metric of 1.7.

We may have two VN Metrics. One for daily, charge-at-home/work, and one for highway travel. 1.5-2 might be great for the former; 15-20 great for the latter.

As you said, the ICE network is saturated. Gasoline service stations were seen as a sure bet during the automobile boom, yet their numbers peaked between 1939-1945 (LINK). A lot of the network was built before GPS, data networks, and routing software. We can probably do a lot better with a lot less. Charge at home is a key for EV mobility.
 

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For long trips, some people with gas cars rent another gas car for the trip. Reasoning include that they can 1) rent a bigger vehicle, 2) reduce wear/tear in their personal vehicle, and 3) ensure they have a late model car that'd be less likely to have problems on the road.

1) Speaks to the question of why people buy a giant truck when they either never or rarely tow. Or who buys a van when they drive alone.
2) If you want your car to last a long time, this will put less miles on it.
3) If you are driving a 10-20 year old car, this might be a good idea.
 

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Fascinating. Thanks for the math. But one thing about the ICEV network being overbuilt: one should take into account the number of vehicles involved. Since 98% of the cars and trucks are ICEV and most EV charging is done at home, the difference between the EV VN merit and the ICE VN merit does not seem so out of kilter. This is not to say that the ICE network is not overbuilt or that it will not be overbuilt as EVs take over.
 

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Perhaps you need a normalization multiplier that takes into account how much time driving the EV is actually spent on a trip where you would need to use the public charging infrastructure. This is basically saying what others above are saying regarding "refueling" at home. If you assume that every EV driver can charge at home and can have a "full tank" every morning, they will only ever be operating within the mode that your expression assumes when they are travelling outside of the range of their EV. When not in this "mode", the EV and ICEV are basically equivalent because of the ICEV's quick refueling time vs. the time it takes to plug in your EV in your garage at night, and the ICEV loses its advantage of quick refueling.

I know this data has been posted here before, but if the multiplier is something like 1% of trips, then that will basically make the ICEV and EV scores much closer, which is why most of us can live with them.
 

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Interesting post.

I agree with the assumption that ICE networks will decline/consolidate. There are too many of them. EV networks never need to reach parity because EVs hardly ever "need" to be refueled on the go. For instance, I plan to buy an affordable EV and use it for local trips, and use a gasser for the longer ones.

The other thing working against EV infrastructure is utilization. They need to be utilized 8 hours of every day to break even on cost. The problem is that the way you increase utilization is by reducing the number of charging stations so that more people are forced to use fewer spots. When it's busy people then have to wait to charge, which is frustrating.
 

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Discussion Starter #9
Perhaps you need a normalization multiplier that takes into account how much time driving the EV is actually spent on a trip where you would need to use the public charging infrastructure. This is basically saying what others above are saying regarding "refueling" at home. If you assume that every EV driver can charge at home and can have a "full tank" every morning, they will only ever be operating within the mode that your expression assumes when they are travelling outside of the range of their EV. When not in this "mode", the EV and ICEV are basically equivalent because of the ICEV's quick refueling time vs. the time it takes to plug in your EV in your garage at night, and the ICEV loses its advantage of quick refueling.

I know this data has been posted here before, but if the multiplier is something like 1% of trips, then that will basically make the ICEV and EV scores much closer, which is why most of us can live with them.
@Vertiformed did the data analysis on NHTSA data https://www.chevybolt.org/threads/question-about-manufacturing-cost-of-onboard-charging-related-equipment.32713/post-501197. Your estimate of ~1% of drives needing away from home charging is right.

Because the VN Metric is intended to capture the effect of a network it may not be applicable to having your own fueling station your garage.

We could however, use only the last term of the last equation to ignore the range question. Merit would be just the ratio of fueling rate/consumption rate. The BOLT with a 7.2kW charge rate would have a merit of 28.

An ICE burning 3 gallons an hour (about 23mpg at 70mph) and fueling at 180 would have a Merit of 60. Probably not far off...
 

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Because the VN Metric is intended to capture the effect of a network it may not be applicable to having your own fueling station your garage.
Yes, individual variation in driving patterns and living situations matters.

For someone who has convenient home charging and driving that generally stays within range of the vehicle (plus a buffer for heater use, side trips, etc.), an EV can be more convenient than an ICE vehicle in terms of "refueling".

But someone who does not have convenient home charging (e.g. many who live in rental housing) need to look for local charging networks, and consider charging speeds at locations that they may use (e.g. workplace charging may not need to be that fast, but some other locations that one does not want to hang around at may need to be fast). And those who go on long road trips would value a fast charging network along highway routes that they plan to use.
 

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Discussion Starter #12
It really depends on how far you drive each day. You can recover 40 miles a night on 120V 12A charging plus more hours during the weekend to catch up, if needed. You can also use the adapter to recombining two separate 120V lines into a 240V and get about 80 miles charge a night.

Very good reference to the ACS (American Community Survey). We seem to think we drive more than we do.

The ACS also points out the cracks in the car network, ICE or BEV. Both are expensive, underutilized and overloaded. Major cities with 30-40 minute one-way commutes in ICEs, will have the same 30-40 minute commutes in BEVs. The air will be cleaner, the roads quieter, but we are still moving at 25 mph.
 
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